US6835849B2 - Synthesis of alkenoate esters from lactones and alcohols - Google Patents

Synthesis of alkenoate esters from lactones and alcohols Download PDF

Info

Publication number
US6835849B2
US6835849B2 US10/618,128 US61812803A US6835849B2 US 6835849 B2 US6835849 B2 US 6835849B2 US 61812803 A US61812803 A US 61812803A US 6835849 B2 US6835849 B2 US 6835849B2
Authority
US
United States
Prior art keywords
recited
group
unsubstituted
substituted
base catalyst
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US10/618,128
Other languages
English (en)
Other versions
US20040059152A1 (en
Inventor
Leo Ernest Manzer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority to US10/618,128 priority Critical patent/US6835849B2/en
Assigned to E. I. DU PONT DE NEMOURS AND COMPANY reassignment E. I. DU PONT DE NEMOURS AND COMPANY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MANZER, LEO ERNEST
Publication of US20040059152A1 publication Critical patent/US20040059152A1/en
Application granted granted Critical
Publication of US6835849B2 publication Critical patent/US6835849B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C07C67/03—Preparation of carboxylic acid esters by reacting an ester group with a hydroxy group

Definitions

  • This invention relates to the synthesis of alkenoate esters from a corresponding lactone and an alcohol, in the presence of basic catalyst. More specifically, this invention relates to the synthesis of alkyl-4-pentenoate esters from 5-methylbutyrolactone and alcohols.
  • Alkenoate esters are valuable precursors and monomers in many processes, for example, in nylon intermediates such as caprolactam and adipic acid.
  • methyl-4-pentenoate ester is a precursor for the production of 5-formylvalerates, which can subsequently be converted to caprolactam without producing ammonium sulfate, by hydrogenation and cyclization of aminocaproates.
  • U.S. Pat. No. 5,144,061 discloses a process for preparing alkenoate esters with a terminal double bond starting from a corresponding 5-, 6-, or 7-membered lactone and an alcohol, in presence of an acid catalyst.
  • U.S. Pat. No. 4,740,613 discloses preparation of 4-pentenoate esters by reaction of gamma-valerolactone with an alcohol in the presence of acidic catalyst at temperatures of 150° C. to 400° C. The reaction produces an isomeric mixture of 4-pentenoate, 3-pentenoates (cis structure and trans structure), and 2-cis-pentenoate. This reaction is represented by the following equation:
  • R is an alkyl group of 1 to 6 carbon atoms.
  • the '613 patent disclosed the reaction of gamma-valerolactone and methanol in the presence of acidic catalysts to give a mixture of methyl pentenoate ester isomers: (1) methyl4-pentenoate ester, (2) cis-methyl-3-pentenoate ester, (3) trans-methyl-3-pentenoate ester and (4) cis-methyl-2-pentenoate ester.
  • This reaction is represented as follows:
  • the '613 patent discloses a maximum distribution of the methyl-4-pentenoate ester of 38%. Attempts prior to the '613 patent reported a maximum distribution of 8% of methyl-4-pentenoate ester (German Laid-Open Application DOS No. 3,412,295 as cited by the '613 patent). In these prior reactions, methyl-4-pentenoate ester was obtained by isomerization of methyl-3-pentenoate ester (70% trans, 30% cis). The 4-pentenoate product was subsequently isolated from such isomeric mixtures by azeotropic distillation.
  • each pentenoate ester isomer can be converted to another isomer, a simple process that produces a particular desired isomer as the major product would be advantageous.
  • the present invention teaches away from using the acidic catalyst for producing alkenoate esters from lactone and alcohol precursors.
  • the invention teaches a process of using basic catalysts to produce alkenoate esters from lactone and alcohol precursors.
  • Three main objectives are achieved from the process disclosed herein: (1) a higher selectivity of 4-pentenoates than hitherto known; (2) a desired distribution of methyl4-pentenoate; and (3) a higher conversion of the lactone precursor to product.
  • the process of the invention provides a selectivity of the methyl-4-pentenoates ester greater than 95%, a distribution of the methyl-4-pentenoate ester isomer in the methyl pentenoate ester product of up to 99% and a corresponding conversion of gamma-valerolactone as high as 70% employing the basic catalyst systems disclosed herein.
  • the process of the instant invention provides a direct, one step method of obtaining a higher yield of methyl-4-pentenoate ester.
  • This invention relates to a process for preparing at least one isomer of alkyl alkenoate ester (III) comprising the steps of contacting lactones of Formula I with an alkanol of Formula II in the presence of a heterogeneous base catalyst to form a mixture containing the corresponding alkyl alkenoate esters,
  • R 1 , R 2 , R 3 , and R4 taken independently are hydrogen, hydrocarbyl or substituted hydrocarbyl, C 1 -C 18 unsubstituted or substituted alkyl, unsubstituted or substituted alkenyl, unsubstituted or substituted cycloalkyl, unsubstituted or substituted cycloalkyl containing at least one heteroatom, unsubstituted or substituted aryl, and unsubstituted or substituted heteroaryl, R 5 and R 6 taken independently are hydrogen or alkyl with 1 to 5 carbon atoms, wherein the total number of carbons of R 5 and R 6 do not exceed 5, and R is alkyl with 1 to 6 carbon atoms.
  • This invention specifically relates to a process for preparing alkyl-4-pentenoate ester isomer in high yields by contacting gamma-valerolactone with alcohol in presence of heterogeneous basic catalyst in the temperature range of from about 250° C. to about 500° C.
  • Alkyl refers to an alkyl group up to and including 12 carbons. Common examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, s-butyl, isobutyl, pentyl, neopentyl, hexyl, heptyl, isoheptyl, 2-ethylhexyl, cyclohexyl and octyl.
  • Aryl refers to a group defined as a monovalent radical formed by removal of a hydrogen atom from a hydrocarbon that is structurally composed entirely of one or more benzene rings. Common examples of aryl groups include benzene, biphenyl, terphenyl, naphthalene, phenyl naphthalene, and naphthylbenzene.
  • Heteroaryl refers to unsaturated rings of 5 or 6 atoms containing one or two O and S atoms and/or one to four N atoms provided that the total number of hetero atoms in the ring is 4 or less, or bicyclic rings wherein the five or six membered ring containing O, S, and N atoms as defined above is fused to a benzene or pyridyl ring. Common examples are furan and thiophene.
  • Hydrocarbyl refers to monovalent groups of atoms containing only carbon and hydrogen, and may be chiral or achiral. Unless otherwise stated, it is preferred in the method of the invention that hydrocarbyl (and substituted hydrocarbyl) groups contain 1 to 30 carbon atoms.
  • Substituted refers to a group attached to a reactant containing one or more substituent groups that do not cause the compound to be unstable or unsuitable for the use of reaction intended.
  • Substituent groups useful in the method of the invention include nitrile, ether, ester, halo, amino (including primary, secondary and tertiary amino), hydroxy, oxo, vinylidene or substituted vinylidene, silyl or substituted silyl, nitro, nitroso, sulfinyl, sulfonyl, sulfonic acid alkali metal salt, boranyl or substituted boranyl, and thioether groups.
  • Distribution refers to the weight percent of a particular methyl pentenoate ester in total amount of methyl pentenoate product.
  • “Selectivity” refers to the weight percent of a particular methyl pentenoate in the total product weight including the weight of unreacted reactants).
  • Conversion refers to the weight percent of a particular reactant that is converted to product.
  • the present invention provides a process for the preparation of one or more pentenoate esters and isomers thereof of a general Formula III comprising contacting at least one lactone of Formula I with at least one alcohol of Formula II, in the presence of a heterogeneous base catalyst to form a reaction mixture containing the corresponding isomers of alkenoate esters, as represented by the following reaction equation,
  • R 1 , R 2 , R 3 , and R 4 taken independently are hydrogen, hydrocarbyl or substituted hydrocarbyl, C 1 -C 18 unsubstituted or substituted alkyl, unsubstituted or substituted alkenyl, unsubstituted or substituted cycloalkyl, unsubstituted or substituted cycloalkyl containing at least one heteroatom, unsubstituted or substituted aryl, and unsubstituted or substituted heteroaryl, R 5 and R 6 taken independently are hydrogen or alkyl with 1 to 5 carbon atoms, wherein the total number of carbons of R 5 and R 6 do not exceed 5.
  • R is alkyl with 1 to 6 carbon atoms.
  • the unsaturated pentenoate esters that are produced by the instant process can be one particular compound or a mixture of isomers.
  • the lactone is gamma-valerolactone (Formula IV) (also known as gamma-methylbutyrolactone, gamma-pentalactone, and 4-methylbutyrolactone) and the alcohol is methanol (Formula V).
  • One or more of the following unsaturated pentenoate esters (Formula VI) are produced therefrom: (1) cis-methyl-2-pentenoate ester, (2) trans-methyl-2-pentenoate ester, (3) cis-methyl-3-pentenoate ester, (4) trans-methyl-3-pentenoate ester, and (5) methyl-4-pentenoate ester.
  • the catalyst useful in the invention is a substance that affects the rate of the reaction but not the reaction equilibrium, and emerges from the process, chemically unchanged.
  • a chemical promoter generally augments the activity of a catalyst.
  • the promoter herein may be incorporated into the catalyst during any step in the chemical processing of the catalyst constituent.
  • the chemical promoter generally enhances the physical or chemical function of the catalyst agent, but can also be added to retard undesirable side reactions.
  • Heterogeneous catalyst refers to a catalyst that operates on reactions taking place on surfaces where the reacting species are held on the surface of the catalyst by adsorption.
  • a suitable base catalyst useful in the process of the invention is either a substance which has the ability to accept protons as defined by Brönsted, or as a substance which has an unshared electron pair with which it can form a covalent bond with an atom, molecule or ion as defined by Lewis.
  • a further description of base catalysts and how to determine whether a particular catalyst is basic is provided in Tanabe, K., Catalysis: Science and Technology , Vol. 2, pg 232-273, ed. Anderson, J. and Boudart, M., Springer-Verlag, N.Y., 1981.
  • Suitable base catalysts include, but are not limited to, metal oxides, hydroxides, carbonates, silicates, phosphates, aluminates and combinations thereof. Preferred are metal oxides, carbonates, and silicates. More preferred are Group 1, Group 2, and rare earth oxides, carbonates, and silicates.
  • the catalysts of the invention can be used directly as commercially obtained or can be prepared from suitable starting materials using methods known in the art.
  • the catalysts employed herein may be used in the form of powders, granules, or other particulate forms. Selection of an optimal average particle size for the catalyst will depend upon such process parameters as reactor residence time and desired reactor flow rates.
  • the catalyst herein may be supported on catalyst support as is common in the art of catalysis.
  • Suitable catalyst supports include, but are not limited to, alumina, titania, silica, zirconia, zeolites, carbon, clays, and combinations thereof. Any method known in the art to prepare the supported catalyst can be used.
  • the support can be neutral, acidic or basic, as long as the surface of the catalyst/support combination is basic.
  • Preferred supports are those which are neutral and have a surface area of greater than about 10 m 2 /g. Commonly used techniques for treatment of supports with metal catalysts can be found in B. C. Gates, Heterogeneous Catalysis , Vol. 2, pp.1-29, Ed. B. L. Shapiro, Tex. A & M University Press, College Station, Tex., 1984.
  • the catalysts of the present invention may further comprise catalyst additives and promoters that will enhance the efficiency of the catalyst. Use of these materials are common and well known in the art (see for example, Kirk - Othmer Encyclopedia of Chemical Technology , Howe-Grant Ed., Vol. 5, pp 326-346, (1993), John Wiley & Sons, New York and Ullmann's Encyclopedia of Industrial Chemistry , Vol. A5, Gerhartz et al., Eds., pp. 337-346, (1986), VCH Publishers, New York).
  • the relative percentage of the catalyst promoter may vary as desired. A useful amount of promoter in the process of the invention is from about 0.01% to about 5.00% by weight of catalyst.
  • a preferred catalyst herein is a metal silicate.
  • silicate is meant an anion consisting of Si, O, and optionally H. These include but are not limited to SiO 3 ⁇ 2 , Si 2 O 7 ⁇ 6 , and SiO 4 ⁇ 4 , and their various hydrated forms. More preferred are silicate salts of Group 2 metals of the Periodic Table of Elements; most preferred is magnesium silicate.
  • One particularly preferred catalyst herein is Magnesol®, a hydrated, synthetic, amorphous form of magnesium silicate produced by The Dallas Group of America, Inc.
  • catalysts are oxides and carbonates of a Group 1, 2, or rare earth metals, optionally supported on a suitable support, and combinations thereof.
  • One method for preparing these catalysts is to dissolve a metal acetate salt in water. A support such as silica is wet with the solution, then calcined. This oxidizes the acetate to the oxide, carbonate, or combination thereof.
  • the more preferred embodiments of the process employ metals from Group 1 or 2 of the Periodic Table. The most preferred embodiment is where the metal catalyst is barium, cesium, or rubidium.
  • Other preferred catalysts include salts of organic acids such as cesium acetate, rubidium acetate, potassium acetate, barium acetate, magnesium acetate, calcium acetate, and mixtures thereof.
  • a preferred catalyst content range of the supported catalyst is from about 1% to about 30%.
  • a more preferred catalytic metal content range is from about 10% to about 25%.
  • a further preferred catalytic metal content range is from about 12% to about 22%.
  • the process is preferably performed in the vapor phase.
  • the process can be performed in any suitable reactor such as, but not limited to a pulse, fluidized bed, fixed bed, steady state riser reactor, and a recalculating solids reactor system.
  • a weight ratio of lactone to alcohol of from about 1/100 to about 100/1 is preferred at the start of the reaction.
  • a weight ratio of about 40/60 to 60/40 at the start of the reaction is further preferred.
  • a weight ratio of about 50/50 is most preferred.
  • a temperature range of from about 250° C. to about 500° C. is preferred for the processes of the invention.
  • a temperature range of from about 275° C. to about 450° C. is further preferred.
  • a temperature range of from about 325° C. to about 400° C. is most preferred.
  • a pressure range of from about 1.0 MPa to about 6.9 MPa is employed for the processes of the invention.
  • a pressure range of from about 2.0 MPa to about 4.0 MPa is preferred.
  • the process of the present invention may be carried out in batch, sequential batch (i.e., a series of batch reactors) or in continuous mode in any of the equipment customarily employed for continuous process (see for example, H. S. Fogler, Elementary Chemical Reaction Engineering, Prentice-Hall, Inc., N.J., USA).
  • the condensate water formed as the product of the reaction is removed by separation methods customarily employed for such separations.
  • selectivities and yields of product may be enhanced by additional contact with the catalyst.
  • yields and selectivities may be increased where the reactor effluent containing a mixture of reactant and product may be contacted additional times over the catalyst under the reaction conditions set forth herein to enhance the conversion of reactant to product.
  • the process of the instant invention may additionally comprise the recovery or isolation of one or more of the pentenoate esters. This can be done by any method known in the art, such as distillation, decantation, recrystallization, or extraction.
  • Magnesol ® magnesium silicate (registered trademark of The Dallas Group of America, Inc. VL gamma-valerolactone or 5-methyl-butyrolactone MP methyl pentenoate ester M4P methyl-4-pentenoate ester t-M2P trans-methyl-2-pentenoate ester t-M3P trans-methyl-3-pentenoate ester c-M3P cis-methyl-3-pentenoate ester cc cubic centimeters Temp. temperature TOS time on stream Dist. distribution Sel. selectivity Conv. conversion
  • Cesium acetate (2.91 g; Sigma-Aldrich Corporation St. Louis, Mo.) was dissolved in H 2 O (14 ml) and the solution was added dropwise into silica (8.07 g; W. R. Grace, Columbia, Md.; Grade 55, 12 ⁇ 20 mesh). The mixture was allowed to stand at room temperature for 2 hours and then the mixture was transferred into an alumina dish. The dish was placed in a horizontal quartz tube and purged with air. The supported catalyst was heated at 120° C. for 4 hours and then at 450° C. for 16 hours in a stream of air. The sample was then cooled to yield 9.87 g of 20% cesium on silica.
  • the sample was then analyzed on a HP 5890 gas chromatograph using a flame ionization detector (with a RTX-1701 column 30 m ⁇ 0.53 mm inner diameter from Restek Co., Bellefonte, Pa.). The detector was held at 50° C. for 3 minutes then heated to 165° C. at a rate of 30° C./min and held for 8 minutes. The selectivity and conversion were then calculated based on normalized area percents. The results are shown in Table 1 below. The table includes the percent VL converted, the percent selectivity to total pentenoate esters, and the distribution of the various pentenoate ester isomers in the total pentenoate esters.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
  • Catalysts (AREA)
US10/618,128 2002-07-15 2003-07-11 Synthesis of alkenoate esters from lactones and alcohols Expired - Fee Related US6835849B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US10/618,128 US6835849B2 (en) 2002-07-15 2003-07-11 Synthesis of alkenoate esters from lactones and alcohols

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US39606902P 2002-07-15 2002-07-15
US10/618,128 US6835849B2 (en) 2002-07-15 2003-07-11 Synthesis of alkenoate esters from lactones and alcohols

Publications (2)

Publication Number Publication Date
US20040059152A1 US20040059152A1 (en) 2004-03-25
US6835849B2 true US6835849B2 (en) 2004-12-28

Family

ID=30115965

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/618,128 Expired - Fee Related US6835849B2 (en) 2002-07-15 2003-07-11 Synthesis of alkenoate esters from lactones and alcohols

Country Status (7)

Country Link
US (1) US6835849B2 (de)
EP (1) EP1532096A1 (de)
JP (1) JP2005533120A (de)
BR (1) BR0312585A (de)
CA (1) CA2492533A1 (de)
TW (1) TW200407295A (de)
WO (1) WO2004007421A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050234294A1 (en) * 2004-04-14 2005-10-20 Usgi Medical Inc. Methods and apparatus for obtaining endoluminal access
WO2014150384A1 (en) 2013-03-15 2014-09-25 Segetis, Inc. Method of manufacture of octanedioic acid, precursors, and derivatives

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AR085717A1 (es) 2011-04-01 2013-10-23 Dsm Ip Assets Bv Proceso para producir acido adipico y diesteres del mismo en un proceso de carbonilacion utilizando ligandos bifosfato bidentados de paladio
AR088124A1 (es) 2011-04-01 2014-05-14 Dsm Ip Assets Bv Proceso para la preparacion de esteres de acido alcanoico en un proceso de carbonilacion utilizando ligandos de bifosfato bidentados de paladio
WO2012175439A1 (en) 2011-06-21 2012-12-27 Dsm Ip Assets B.V. Process to produce valerolactone from levulinic acid
WO2013107904A1 (en) 2012-01-19 2013-07-25 Dsm Ip Assets B.V. Process to produce alkanoic acid esters in a carbonylation process using lewis acids as acid promotor
WO2014163506A1 (en) 2013-04-05 2014-10-09 Universiteit Leiden Process to prepare epsilon-caprolactam
JP2018188402A (ja) * 2017-05-10 2018-11-29 宇部興産株式会社 ペンテン酸エステルの製造方法
DE102018114441A1 (de) 2018-06-15 2019-08-01 Leibniz-Institut Für Katalyse E.V. An Der Universität Rostock Verfahren zur Herstellung von endständig ungesättigtem Alkencarbonsäureester aus Lactonen

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031493A (en) 1958-06-03 1962-04-24 Wacker Chemie Gmbh Process for the production of unsaturated carboxylic acid esters
US4740613A (en) 1986-03-19 1988-04-26 Basf Aktiengesellschaft Preparation of 4-pentenoates
US4777285A (en) 1986-03-19 1988-10-11 Basf Aktiengesellschaft Preparation of alkenecarboxylates
US5144061A (en) 1986-11-07 1992-09-01 Basf Aktiengesellschaft Preparation of alkenecarboxylic esters

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031493A (en) 1958-06-03 1962-04-24 Wacker Chemie Gmbh Process for the production of unsaturated carboxylic acid esters
US4740613A (en) 1986-03-19 1988-04-26 Basf Aktiengesellschaft Preparation of 4-pentenoates
US4777285A (en) 1986-03-19 1988-10-11 Basf Aktiengesellschaft Preparation of alkenecarboxylates
US5144061A (en) 1986-11-07 1992-09-01 Basf Aktiengesellschaft Preparation of alkenecarboxylic esters

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050234294A1 (en) * 2004-04-14 2005-10-20 Usgi Medical Inc. Methods and apparatus for obtaining endoluminal access
WO2014150384A1 (en) 2013-03-15 2014-09-25 Segetis, Inc. Method of manufacture of octanedioic acid, precursors, and derivatives

Also Published As

Publication number Publication date
US20040059152A1 (en) 2004-03-25
TW200407295A (en) 2004-05-16
CA2492533A1 (en) 2004-01-22
EP1532096A1 (de) 2005-05-25
BR0312585A (pt) 2005-04-12
WO2004007421A1 (en) 2004-01-22
JP2005533120A (ja) 2005-11-04

Similar Documents

Publication Publication Date Title
EP1165536B1 (de) Verfahren zur herstellung von alpha-methylenlactonen
KR960000041B1 (ko) 불포화 카르복시산 에스테르의 제조방법
US4420622A (en) Process for the preparation of a 5-alkyl-butyrolactone
EP0379691B2 (de) Verfahren zur Herstellung von ungesättigter Carbonsäure oder ihrem Ester
KR20040027935A (ko) 락톤으로부터의 불포화 니트릴의 합성
US6835849B2 (en) Synthesis of alkenoate esters from lactones and alcohols
US4942259A (en) Process for preparing n-vinyl amides
US4072660A (en) Process for the manufacture of resorcinols
US4740613A (en) Preparation of 4-pentenoates
US20040006244A1 (en) Process for making ethyencially unsaturated acids and acids
EP0550762B1 (de) Verfahren zur herstellung von nitrilen
US5457222A (en) Process for producing nitrile
JP3561178B2 (ja) ニトリルの製造方法
US4874889A (en) Isomerization of 2-pentenoates to 3-pentenoates
JPH06316555A (ja) ５−シアノ吉草酸エステルの製造方法
JP2884637B2 (ja) 不飽和カルボン酸エステルの製造法
US6429339B1 (en) Method for producing cyclopentanone
EA022077B1 (ru) Новый способ синтеза агомелатина
JPH0250088B2 (de)
JP2660169B2 (ja) ３級ｎ−アルケニルカルボン酸アミド類の製造用触媒及び３級ｎ−アルケニルカルボン酸アミド類の製造方法
US3031493A (en) Process for the production of unsaturated carboxylic acid esters
US7247753B2 (en) Method for producing macrocyclic ketones by means of dieckmann codensation in the gas phase
US5616773A (en) Preparation of 5-cyanovalerates
US6288264B1 (en) Process for preparing cyanoacetamide
US4772746A (en) Preparation of 4-pentenoates

Legal Events

Date Code Title Description
AS Assignment

Owner name: E. I. DU PONT DE NEMOURS AND COMPANY, DELAWARE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MANZER, LEO ERNEST;REEL/FRAME:014207/0561

Effective date: 20031110

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20081228